The present invention relates in general to devices and methods for dispensing flowable materials having high viscosities, and more particularly to the dispensing of soft serve frozen confections such as ice cream and the like.
A frozen confection, such as ice cream, frozen yogurt, sherbet, or sorbet, is termed "soft serve" when it is at a temperature within a range of approximately 10 to 20.degree. F., for example 18.degree. F., so as to have a viscosity that will enable it to flow through a dispensing nozzle into an edible cone or other suitable container whereupon the soft serve confection is immediately consumed. Traditionally, complex machines have been provided at retail outlets to manufacture, store and dispense soft serve frozen confections. The complexity of the machines makes them costly not only to acquire but also to maintain, both from an operational and a hygienic standpoint. Also, the quality of the soft serve confection is difficult to control due to variations in the ingredients loaded into the machine, and due to variations in the level of skill of the machine operators. Further, it is difficult to provide, at the retail level, a wide variety of types and flavors of soft serve frozen confections since the noted machines must each be dedicated to providing only a few types and flavors of confections at any given time, and since the number of machines per retail outlet is limited by cost and space considerations.
As an alternative to the above, it has been proposed that soft serve frozen confections be manufactured at a central facility, and then stored at the facility in portable containers at a low storage temperature of 0.degree. F. or below. By use of a central manufacturing and storage facility, the cost and quality of the frozen confections could be more readily controlled. Also, an inventory of prefilled containers providing a wide range of types and flavors of frozen confections could be established. The containers could then be shipped on demand from inventory to retail outlets wherein they would be thawed or tempered to a "soft serve" temperature. The containerized soft serve frozen confections could then be dispensed at the retail outlet from a simpler and more compact machine that would only function as a dispenser and storage means.
Examples of dispensers for containerized soft serve confections are illustrated by U.S. Pat. Nos. 5,048,724, 5,069,364, 5,215,222, and 5,244,277, all of which are expressly incorporated herein. The noted patents disclose dispensers wherein collapsible or otherwise deformable containers are mechanically compressed to expel or extrude soft serve frozen confections therefrom for each individual serving. While the noted compression type soft serve dispensers arguably represent an advance in the art, it has been found that repeated compression of soft serve frozen confections, which can contain up to 40% air, may degrade the quality of the dispensed product. It is believed that repeated pressurization of the frozen confection within the container causes undesirable ice crystals to form within the confection, degrading the taste and texture of the dispensed confection. Although this effect is small or almost negligible for each pressurization/depressurization cycle, since the entire volume of confection within the containers of these patents is repeatedly pressurized the cumulative effect is substantial and noticeable.
Also, the discharge rate from the earlier noted patented devices, which mechanically compress the product, is highly dependent upon product viscosity and, therefore, product formulation and temperature. For example, high fat content chocolate ice cream having a relatively high viscosity may have to be dispensed at a higher "soft serve" temperature, or a higher pressure, than a lower viscosity sorbet.
It is therefore an object of the present invention to provide a dispenser for containerized frozen confections and the like of the soft serve type that can operate over a relatively wide "sort serve" temperature range wherein frozen confections at the same temperature, but of substantially different viscosities can be dispensed. It is a further object of the present invention to provide a dispenser that will eliminate repeated compression or pressurization of the frozen confection within the container, and minimize compression or pressurization of dispensed frozen confection, so as to avoid or at least minimize the above noted problems associated therewith. It is also an object of the invention to provide a dispenser that will dispense ice cream in controlled predetermined amounts for purposes of portion control. It is a further object of the invention to provide a delivery means including a dispensing valve which is operable to dispense viscous material with a minimum of compression or pressurization of the viscous material being dispensed therefrom.
It is to be noted that while the above background and subsequent description of the invention focus mainly on the dispensing of soft serve frozen confections, it is clearly contemplated by the inventors that the invention may have applications to the dispensing of other high viscous food products, such as prepared vegetables and nutritional supplements.